Re: exceptions with null pointers
Denis Petronenko wrote:
in the following code i have segmentaion fault instead of exception.
Why? What i must to do to catch exceptions in such situation? Used
compiler: gcc version 3.3.6 (Debian 1:3.3.6-13)
int main()
{
try{
int* p = NULL;
*p = 4;
}
catch(...){
cout << "exception" << endl;
}
return 0;
}
Dereferencing a null pointer produces *undefined behaviour*. It
may (allowed to) throw an exception, or it may send a nasty e-mail
to your supervisor and then reformat your hard drive. Expecting
something *definite* from a construct that has undefined behaviour
is silly.
You can't do anything certain to catch an exception. Even if you
figure something out about your system/compiler which will lead you
to a solution, it won't work on a different system or compiler, and
therefore cannot be classified as a C++ solution. A simple answer
to this is, "check your pointer for being null before dereferencing".
V
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